RX: ignore all local 127/8 IFF_LOOPBACK interfaces

Currently RX lists all non-127.0.0.1 interfaces in the interface list,
even those that are specified as IFF_LOOPBACK, to accomodate certain
special cases where IFF_LOOPBACK interfaces should be advertised.
However, this makes us advertise e.g. a 127.0.0.2 lo interface. So
instead, skip all interfaces that are both in 127/8 and claim they are
IFF_LOOPBACK, as this will skip a stray 127.0.0.2, but should not
confuse the special cases.

Change-Id: I60a4ed5330252078e2f58894195f9b68ec70dcfa
Reviewed-on: http://gerrit.openafs.org/2376
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>

diff --git a/src/rx/rx_getaddr.c b/src/rx/rx_getaddr.c
index b917f8e39e990bff1eb99e2801787e01366b6e4e..ea8fa598cd00c41352ace230e64522f597a3c054 100644 (file)
--- a/src/rx/rx_getaddr.c
+++ b/src/rx/rx_getaddr.c
@@ -139,6 +139,18 @@ rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo)
 }
 #endif
 
+static_inline int
+rxi_IsLoopbackIface(struct sockaddr_in *a, unsigned long flags)
+{
+    afs_uint32 addr = ntohl(a->sin_addr.s_addr);
+    if (rx_IsLoopbackAddr(addr)) {
+       return 1;
+    }
+    if ((flags & IFF_LOOPBACK) && ((addr & 0xff000000) == 0x7f000000)) {
+       return 1;
+    }
+    return 0;
+}
 
 /* this function returns the total number of interface addresses 
 ** the buffer has to be passed in by the caller
@@ -240,7 +252,7 @@ rx_getAllAddr_internal(afs_uint32 buffer[], int maxSize, int loopbacks)
            if (count >= maxSize)       /* no more space */
                dpf(("Too many interfaces..ignoring 0x%x\n",
                       a->sin_addr.s_addr));
-           else if (!loopbacks && rx_IsLoopbackAddr(ntohl(a->sin_addr.s_addr))) {
+           else if (!loopbacks && rxi_IsLoopbackIface(a, ifm->ifm_flags)) {
                addrcount--;
                continue;       /* skip loopback address as well. */
            } else if (loopbacks && ifm->ifm_flags & IFF_LOOPBACK) {
@@ -430,7 +442,7 @@ rx_getAllAddr_internal(afs_uint32 buffer[], int maxSize, int loopbacks)
        }
        if (a->sin_addr.s_addr != 0) {
             if (!loopbacks) {
-                if (rx_IsLoopbackAddr(ntohl(a->sin_addr.s_addr)))
+                if (rxi_IsLoopbackIface(a, ifr->ifr_flags))
                    continue;   /* skip loopback address as well. */
             } else {
                 if (ifr->ifr_flags & IFF_LOOPBACK)